Arc welding apparatus



June 18, 1940. J. P. TRIPP ac WELDING APBARATUS Filed March 7, 1938 5 Sheets-Sheet l I 8 7 mm? PW; mm mm; wn. a Y U 0 P w Q wm mm. m P- T m a 0. A Emma Q m mm Q V B u \\mm II. II. mm 2 E Hm hw m 9 mm mv L June. 18. 1940. J. p T P 2,205,002

' mo WELDING APPARATUS Filed March 7 1938 5 Sheets-Sheet 2 FIGJa I I INVENTOR \I. P.1'RIPP ATTORNEY June1s,1940. J, P, T IPP- v 2,205,002

RC WELDING APPARATUS Filed march 7, 1958 s Shets-Sheet 3' INVENTOR ATTORNEY J. P. TRIPP ARC WELDING APPARATUS Flled March 7, 1938 June 18, 1940.

all

I ATTORNEY mp WP wn June 18, 1940. J. P. TRIPP ARC WELDING APPARATUS Filed March 7, 1938 5 Sheets-Sheet 5 FIGS INVENTOR- ATTORNEY P W m a 5 a 7 m .E B I R 0 w P- 5 Paw w J 1 wnmr 1W1". mm 0 0 m m m .r s TE 9 C U .H d! wwnr mu T 6 I I I I I hbh n P M 2 6 1 5 H 1 5 G 2 E.% W I m 1 F Patented June 18, 1940 UNITED STATES.

PATENT OFFICE 1 Ulaim.

This invention relates to improvements in arc welding machines used in connection with the seam welding of plates or cylindrical objects such as sheet metal pipes, tanks and the like.

It is an object of this invention to provide a compact, self-contained machine by which seam welding operations, particularly the longitudinal seam welding of pipes and tanks, may be easily and quickly accomplished without the assistance ofoverhead cranes,hoists or other separate work lifting devices usually required for positioning the work with reference to the welding head. To this end the machine is provided with a work-transporting truck which serves to push the pipe or other cylindrical work piece onto an elevated, horizontally extending work-supporting arm, to which the work is fastened during the seam welding operation. The truck preferably travels on a normally horizontal platform which is pivoted so thatit may be swung downwardly to lower the truck out of engagementwith the work after the latter has been placed on said arm.

It is also an object of this invention to provide a machine of the character described which readily lends itself to the use of either electro-magnetic or mechanical clamping means for anchoring the work to the work-supporting arm.

A further object is to provide-a compact ma-' chine of the character described in which the welding head is suspended from a truck running on track rails carried by a horizontal portion of the machine frame overlying the elevated worksupporting arm, said truck being power driven so that it may be readily moved in the lengthwise direction of the work or seam.

vA further object is to provide a machineof the character described in which a backing plate is mounted on a small truck carried by the worksupporting arm, said truck being coupled to the welding head truck to travel therewith.

A still further object is to provide improved means for supporting the cables through which current is supplied to the welding head and other elements of the machine.

Proceeding now to a more detailed description reference will be had to the accompanying drawings, in which- Figure 1 is a side elevation-of a complete weld ing machine installation designed in-accordance with this invention.

' Figure 2 is an end elevation looking toward the right hand end of the installation appearing in Figure 1. Figure 2 also shows an auxiliary cable ted from Figure 1.

Figure 3 is an end elevation looking toward the left hand end of the installation appearing in Figure 1.

Figure 4.is a top plan view of the installation appearingin Figures 1 and 2.

Figure 5 is a fragmentary top plan view ofthe work-sup'porting arm and backing plate assembly carried thereby. This view shows the manner in which the backing plate and the backing plate truck are mounted to travel longitudinally of the work-supporting arm. It also shows the manner in which magnets may be attached to opposite sides of the arm to provide magnetic clamp-' ing or work-holding means.

Figure 6 is a transverse sectional view along the line 6-6 of Figure '5.

Figure 7 is a longitudinal sectional view along the line |--1 of Figure 5, and

Figure 8 is a top plan view of the backing plate truck as it appears with the backing plate removed therefrom.

Figure 7a is a longitudinal sectional view through the hollow backing plate showing the manner in which the return pipe of the backing plate cooling system is directed upwardly into a recess of the backing plate cover to prevent trap ping of air that might result in interference with the circulation of the cooling medium.

The particular machine shown in the present drawings is designed to facilitate the longitudinal seam welding of pipes, tanks andother cylindrical objects by the welding process known to the trade as the Unionmelt" process. It therefore comprises certain conventional elements well known in-connection with this particular welding process. Such elements, include the welding head 5, electrode reel 6, flux tank I. centrifugal compressor 8, and compressor operating motor 9. 'The head 5 is suspended from a welding head truck 10 by a suitable suspension member ll (Figure 1). The reel 6 is mounted on a standard I2 rising from the truck ID. A bare wire electrode li3is suitably passed from reel 6 to the welding head 5 as indicated in Figure 1. The flux tank I is mounted on truck 40 and is provided with the usual flexible flux discharge pipe l5 (Figure 1) through which the flux is fed to the weld through the welding head 5 in the manner characteristic of the Unionmelt process. According to this process part of the flux is thus fused over the weld to form a protective coat which remains until the molten steel from the electrode solidifies and cools. The surplus flux is returned to tank i through nozzle I6 and pipe "a by the suction of compressor 8 whose suction side is connected to the upper portion of tank I by suction pipe l1. Suitable filter bags (not shown) are arranged in the upper portion of tank I in accordance with the Unionmelt process to prevent the flux being drawn into the suction pipe I I by the compressor 8. The compressor 8 is driven from motor 9 through the agency of a suitable belt drive l8. The traction wheels H of truck l0 travel on overhead rails lying above and parallel with the length of ti e work or pipe 2! when the latter is arranged ui the work-supporting arm A as indicated by dotted lines in Figure 1. The rails 20 are mounted on laterally spaced eye beams 23 supported by vertical frame structures 24 and 25 rising from the base frame 26. The eye beams 23 are spaced apart to provide an intervening space along which the welding head suspension member I l travels as the welding head 5 and truck III are shifted to different longitudinal seam welding positions along the length of the work 2!.

The propelling mechanism of truck 10 is substantially the same as the propelling mechanism of the power driven truck embodied in the arc welding mechanism described in my prior United States Patent No. 1,991,128, dated Feb. 12, 1935, and in my co-pending application Serial No. 184,120, filed Jan. 10, 1938. Such mechanism (see Figure 4) comprises a rapid travel motor 21 and a slow speed travel motor 28 adapted to be used alternately for propelling the truck at different speeds depending on operating conditions. Motor 21 serves to drive the truck axle 29 through a suitable drive connection comprising the gearing 30 and magnetic clutch 3|. Motor 28 serves to drive the same axle through a similar drive connection comprising the gearing 32 and magnetic clutch 33. The magnetic clutches 3| and 33 are electrically interlocked as described in my prior Patent 1,991,128, or in any other suitable manner to prevent simultaneous engagement thereof. When operating current is supplied to motor 21 the magnet of clutch 3| is automatically energized to establish a drive connection between the motor 2'! and axle 29. This motor is used to effect rapid or high speed travel of the truck l0 when returning the welding head 5 to its starting position after completion of a seam welding operation or whenever it is desired to quickly bring the welding head to a desired position. By deenergizing the motor 2'! and energizing the motor 28 the truck in and welding head 5 may be moved at a desired welding speed.

In order to prevent slippage of the truck wheels I!) on the, track rails 20 one of said wheels is provided with a gear 19a (Figure 4) meshing with a rack I9?) carried by one of the rail supporting beams 23.

The welding and control cables leading to the welding head and electrical equipment are indicated at 45, 46 and H in Figures 1, 2 and 4. As shown in Figure 2. these cables are looped over a pulley 49 carried by a pulley frame 49a rising from a cabinet structure 4% arranged at one side of the frame supporting the welding head truck. The welding cables 45 are passed from the pulley 49 to suitable contacts on the welding head 5 as indicated at 5| in Figure 1. These cables are clamped to a plate 52 carried by the fiux return pipe l6a. They are also passed around a guide block 53 (Figure 2) on truck ill and secured in place by additional clamps 54 and 55. The cable 41 supplies current to motor 9 and is passed to said motor through a rigid conduit 5'! (Figs. 2 and 4) carried by the truck l0. Cable 45 is also passed over the guide block 53 to a junction box 58 on truck I0 and is preferably secured in place by the clamp 55. The cabinet structure 491) carries the control panel 59, magnetic starter 60, generator 6! and other accessories which need not be described in detail since they are not claimed as part of the present invention.

The work supporting arm A is supported adjacent one end by the vertical frame structure 24. This arm comprises side members 65 and a bottom member 66. The space between the upper edges of the side members 65 is left open except at points adjacent opposite ends of the arm where front and rear cover plates 61 and 61a (Figs. 1 to 3 inclusive) are provided. The wheels 5a (Fig. l) of the welding head 5 are supported on the front cover plate 61 when the welding head is arranged at the free end of the arm A preparatory to being moved rearwardly over the work 21. As the wheels 5a pass beyond the rear end of the pipe during the welding operation they pass onto and are supported by the rear cover plate 51a. A backing plate carriage 68 (see Figs. 2 and 5 to 8 inclusive) is arranged to travel on the bottom plate 66 of arm A between the side members 65. This carriage supports the backing plate 10 and the backing plate adjusting frame H. The backing plate 10 comprises a hollow casing provided with an internal longitudinally extending partition 12,.dividing the in terior of the casing into two compartments connected, at one end of the partition, by a communication passage 13 (Fig. l). Cooling fluid is supplied to the compartment at one side of partition 12 by a pipe 14 and is withdrawn from the compartment at the opposite side of the partition by a pipe 15. At the ends remote from the hollow backing plate 10 the pipes '14 and 15 are connected by flexible hose sections 11 and 18 (Figs. 1 and 3) and rigid conduits l9 and 80 to flexible water supply lines 8| and 82. The rigid conduit sections 19 and 80 are fastened by clamps 83 to a vertical member 84 which is carried by and travels with the truck ill. The lower end of member 84 is also fastened to one end of a draw bar 85 as indicated at 86 in Fig. 1. The remaining end of draw bar 85 (see Fig. 8) is provided with a yoke 81 which is fastened by a coupling pin 88 to the side members 90 of the backing plate carriage 68. It will thus be seen that the backing plate carriage 68 travels with the welding head truck l0 and causes backing plate 10 to follow the travel of the welding head 5 along the seam. In other words the backing plate moves with the welding head and always maintains its proper position relative thereto.

As shown in Figure 7a. the backing plate return pipe 15 is provided. within the hollow casing of the backing plate, with an elbow 15a and an upwardly projecting nipple 15b. In order to prevent air trapping, the upper end of the ripple 15b is disposed within a narrow downwardly facing groove 10a formed in the backing plate cover.

Backing plate 10 is pivotally mounted between side' members 92 of backing plate adjusting frame Ti as indicated at 93 (Figs. 6 and '7). The side members 92 of frame H are pivoted at one end to a bracket 84 mounted on carriage 88. The remaining ends of members 92 are formed integral with a plate 85 resting on the piston rod 91 of a piston 88 operating in cylinder 99 of the backing plate carriage 68. Air is supplied to and exhausted from the lower end of cylinder 99 through pipe I00 to raise and lower the piston 98.

. end of the bolt, to raise the free end of the clamp- When air is exhausted from cylinder 9! the piston 98 is lowered and permits the backing plate adjusting frame II to swing downwardly about the pivot 93 until the backing plate I0 is below1 the upper edges of the side members of the work supporting arm A. This permits the work to he slipped onto the arm A, as hereinafter described, without interference .by the backing plate. After the work has been properly positioned on the work supporting arm piston 92 is raised by air suppliedthrough pipe Hill and acts against plate to raise backing plate I0 into contact with the work (see Figs. 6 and 7) As shown in Fig. 3, the end of pipe I00 remote from cylinder 98 is connected, by flexible hose section IIlI and rigid conduit section III2, to a flexible air supply'pipe I03. The air and water supply pipes BI, 82 and-I03 are provided with suitable valves I 05, I0 and II".

When the work His arranged on the supporting arm A, as shown in Figs. 1, 6 and 7, it may be secured in place in various ways. In the present application I have disclosed both mechanical and magnetic clamping mes. When the mechanical clamping means is used the magnetic clamping means isomitted and vice versa.

The mechanical clamping means comprises a pair of hollow clamping arms Ill located above and at opposite sides of the work supporting arm A. One end of each clamping arm II. is

pivotally fastened to the corresponding end of the work supporting arm A by means of the depending brackets III (Fig. 3) and pivot shaft H2. Each arm III) carries a plurality of clamping' bars Ilt'having one end pivoted thereto and the other end disposed to bear against the work portion of each clamping barand extends up-' wardly within the associated clamping arm IIO. Each bolt is encircled by Q spring I ll which normally acts against an abutment I I6, at the upper ing bar H3. During welding operations, the clamping bars II3 are pressed to the work, against the opposition of springs Ill, by pressure applying plungers III workingin air cylinders I I8 attached to the inner sides of the clamping arms I III. Air is supplied to and exhausted from these cylinders-in any suitable manner so that the plungers may be forced downwardly to apply the clamping bars or may be sufllciently relieved of air pressure to permit release of the clamping bars by the springs H5.

The work supporting arm A is provided with latches I20 pivoted thereto as indicated at I2I.

The free ends of these latches are provided with hooks I22 adapted to be engaged over pins I23 carried by the pivotally mounted clamping arms Hi. If thel operator fails to hook these latches over the pins I23 before operating the clamping bars I I3 the clamping arms III will revolve about their pivotal axes H2 and will be undamaged.

If desired the clamping arms Ill and associated clamping bars III may be replaced by A bolt I I4 is attached to the intermediate magnetic clamping or work holding means comprising a, series of magnets I25 fastened to opposite sides of the work supporting arm A. These magnets may be energized in any suitable manner to attract the work 2| and hold it in place on i the clamping arm A.

welding process in which the arc is submerged in and concealed by the welding flux. With this in mind .the work holding magnets provided in accordance with this invention are arranged to guard against magnetic deflection of the are when the magnetic work holding means is employed' in place of the mechanical clamping means; To this end the magnets are arranged as shown in-Fig. 6 so that one pole piece of each magnet is formed by the adjacent side 65 of the arm A while the remaining pole piece is formed by a 'plate I25d spaced outwardly from the member 65. This locates the magnetic field of each magnet so that the main flux path is along the circuit indicated by the arrow I25b. It will thus be seen that the main magnetic flux of each magnet is located to one side of the welding zone andclear of intersection with the arc. Inpractice it has been found that, with this arrangement of the magnets, any magnetic leakage which is dispersed so far as to reach the welding zone is of such low intensity as to produce no objectional magnetic deflection of the arc. The pole pieces of each magnet I25 are preferably bridged by thin brass sheets I250 which are provided to protect the residual magnetism when the magnets are deenergized.

The pipe' or work 2| is positioned on the work supporting arm A by means of a work supporting truck B on which the work is initially placed. This truck is provided with work supporting rollers I21 so th'atthe work may be freely rotated on the truck to any desired position prior to being pushed onto the work supporting arm A.

The wheels I28 of truck 3 travel on the rails I29 mounted on a movable platform I30. One end of this platform is mounted to swing about a pivotal axis Ill. The other end is provided with vertically extending brackets I22 carrying a roller shaft III equipped with rollers I 14. These rollers are arranged to ride the peripheral edges of suitable eccentric discs I" fixed to a shaft I36 which is driven through suitable gearing III by an electric motor I" mounted'on a stationary base I39. The platform m is normally disposed in a horizontal position and the truck I2! is moved to the left from the position shown in Fig. 1 to .a position beneath the work supporting arm A. During this movement of the truck the work 2I is passed onto the work supp ting arm A. The motor I 3| is then operated to turn the eccentric discs I" in a platform ,lowering diection whereby the truck I2I is moved downwardly to leave the work 2i suspended on the arm A to which the work is then clamped by either of the methods previously described.

Having thus described my invention, what .I claim is:

In electric welding apparatus the combination of a horizontal work supporting arm, a backing plate carriage supported by and movable longitudinally of said arm, a backing plate supporting frame having one end pivoted to said carriage I to provide a horizontal axis about which the frame is swingable in a vertical direction, a backing plate pivoted to said frame to permit the backing plate to assume a horizontal position irrespective of the angular inclination of the frame with reference to said carriage and means for-raising and lowering the free end of said frame.

.1081; P. TRIPP. 

